End effector with multiple pick-up members

ABSTRACT

An end effector for use with a moving device has a frame and a plurality of operational members mounted for movement on the frame. The effector also has an actuation mechanism directly connected to a first operational member and is operable to move the first operational member from a first position to a second position, and from the second position to the first position. A linking apparatus is provided for linking the first operational member to a second operational member. The actuation mechanism moves the first operational member from the first position to the second position, and results in the second operational member being moved by the linking apparatus from a third position to a fourth position. The operational members can be pick up members for picking up items at one pitch and releasing them at a second pitch.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application of U.S. patent application Ser. No.12/214,828, filed Jun. 23, 2008 (now U.S. Pat. No. 8,240,726 issued onAug. 14, 2012), which is a continuation application of U.S. patentapplication Ser. No. 10/420,075 filed Apr. 22, 2003 (now U.S. Pat. No.7,390,040, issued on Jun. 24, 2008), which is related to U.S.Provisional Patent Application Ser. No. 60/374,408 filed Apr. 22, 2002,the entire contents of all applications being hereby incorporated hereinby reference.

FIELD OF THE INVENTION

The present invention relates to end-effectors for use with devices suchas robotic arms.

BACKGROUND OF THE INVENTION

End-effectors attached to devices such as robotic arms are well known.These end-effectors often have operational members that performoperations on items. One common type of operational members are pick-upmembers which can be used to pick up, move and release items.

The use of devices as such as robotic arms with end effectors, that canperform operations on items, is also well known in various industries,such as for example, in the packaging industry. Such robotic arms use avariety of end effectors, for example, to move items from an articlefeed conveyor into open receptacles such as for example, cardboardboxes. Advantageously, robotic arms and their end-effectors can be movedthrough a wide range of orientations and positions in athree-dimensional space. One example of the use of a robotic arm and endeffector to package items is disclosed in U.S. Pat. No. 5,060,455(“Robotic Case Packaging System and Method”), the contents of which arehereby incorporated by reference.

Robotic arms are traditionally constructed as a cascade of severaljoined sections, each of which can be rotated and translated in athree-dimensional space so as to achieve a desired position of the endsection of the robotic arm, and thus achieve a desired position andorientation in the three-dimensional space for the end effector attachedto the end section of the robotic arm. Disadvantageously, becauseseveral different sections of traditional robotic arms have to beseparately controlled, such robotic arms are very slow, and thereforenot particularly well suited for use with high rate packaging systems.However, a more recent robotic arm that can move at very high speeds isthe robotic arm disclosed in U.S. Pat. No. 4,976,582 (“Device for theMovement and Positioning of an Element in Space”), the contents of whichare hereby incorporated by reference. This robotic arm, sometimesreferred to as a “Delta” robot or a “Spider” robot uses threeindependent and non-joined control arms extending from a base elementand attached to a movable element to position and orient the movableelement in three-dimensional space. An end effector is attached to themovable element. Preferably, the end effector can be rotated about itscenter by connecting a rotatable shaft that is connected to a motorpreferably positioned at the base element of the Delta robot.Advantageously, this design allows the movable element to be moved ataccelerations ranging between 12 G to 50 G.

Because of the high speeds at which Delta robots can move, Delta robotshave been used in industry to package items. For example, a packagingsystem manufactured by SIG Demaurex uses a Delta robot to packagevarious food items. This packaging system uses an end effectorcomprising of six pick-up members to simultaneously pick-up six items.Gripping of the items in the packaging system is usually achieved bysuction cups on the end effector which grip one or more items. Thesuction is applied to the cups through the use of a vacuum system. Oncethe end effector attached to the movable element in the Delta robot haspicked up the items, the end effector is moved to a position proximate areceptacle at some desired position relative to the rest of thepackaging system. At this release position the items can be depositedinto the receptacle.

Advantageously, the positions of the pick-up members on the end effectorcan be adjusted so that the pick-up members can pick-up several items atthe same time, that are far apart from each other. Subsequently theitems held by the end-effector can be converged, by moving the pick-upmembers toward each other, thus bringing the items closer to each other.Having adjusted the spacing of the items, they can be deposited into asingle receptacle in a more closely packed configuration.

Known designs of end effectors for simultaneous transport of a number ofitems use pneumatic rods, or equivalent actuation mechanism, that areattached to each one of the pick-up members on the end effector tocontrol the positions of those pick-up members on the end effector. Oneof the main problems with such end effector designs is the highcomplexity involved in individually controlling the position of thepick-up members. Additionally, the physical size of each actuationdevice places constraints on the maximum number of actuation devicesthat can be combined to form the actuation mechanism of an end effector.

Another problem with the use of Delta robots to package items is thelimitation of the load weight that can be carried by the end effectordue to the high speeds at which the movable element, and the endeffector attached to it, move. A heavy weight load would necessarilyreduce the maximum acceleration that can be obtained for the movableelement and the end effector. Thus, one of the important considerationsin the design and use of an end effector is the weight of the endeffector. The lower the weight of the end effector, the more weight thatcan then be picked-up by the end effector for transport to a receptacle.With current designs of end effectors for simultaneous transport ofmultiple items, the use of separate pneumatic rods to control individualpick-up member adds considerable weight to the overall weight of the endeffector. This reduces the total weight that can be picked-up by the endeffector for transporting an article to a receptacle.

It would therefore be desirable to have a lighter weight end effector,that uses a less complex and cumbersome actuation mechanism to controlthe positions of the pick-up members on the end effector.

It is also desirable to be able have an end effector which can perform afirst operation on a group of several items spaced at a first pitch andthen group those items into at least two groups, each item in the twogroups being at a second pitch, and perform a second operation on theitems in both groups at the same time.

SUMMARY OF INVENTION

It is therefore desirable to provide for an end effector consisting ofmultiple pick-up members for transporting items from one location toanother location, which uses a simple actuation mechanism to control thepositions of the pick-up members on the end effector. It is also desiredto be able to economize on the weight requirements of the actuationmechanism of the end effector so as to allow the end effector to pick-upand transport a larger number of items at high speeds.

In one aspect of the invention there is provided an end effector for usewith a moving device, the end effector comprising: a) a frame; b) aplurality of operational members mounted for movement on the frame; c)an actuation mechanism directly connected to a first operational memberof the plurality of operational members and operable to move the firstoperational member from a first position to a second position, and fromthe second position to the first position; (d) a linking apparatus forlinking the first operational member to a second operational member ofthe plurality of operational members; wherein when the actuationmechanism moves the first operational member from the first position tothe second position, the second operational member is moved by thelinking apparatus from a third position to a fourth position, and whensaid actuation mechanism moves said first operational member from saidsecond position to said first position, said second operational memberis moved from said fourth position to said third position.

In yet another aspect of the invention there is provided a method forlifting and transferring items from a first location to a receptacleusing an end effector attached to a robot, said method comprising: a)moving said robot to position said end effector above a first batch ofsaid items; b) actuating one of a plurality of pick-up members slidablymounted on the body of said end effector to a position directly above afirst item of said first batch of said items, and using linking meansconnecting the remainder of said pick-up members to said one pick-upmember to pull said remainder of said pick-up members to a positiondirectly above the remainder of said first batch of said items; c)lowering said end effector so that said pick-up members can pick up saidfirst batch of said items; d) raising said end effector; e) moving saidrobot to reposition said end effector above a receptacle: f) moving saidone pick-up members to a converged position, and causing said remainderof said pick-up members connected to said actuated members to convergesaid pick up members using said linking apparatus; g) lowering said endeffector toward said receptacles so that said first batch of said itemsare placed inside said receptacle; h) releasing said first batch of saiditems from said pick-up members; i) raising said end effector from abovesaid receptacle; and j) repeating steps a-i to transfer the next batchof said items into a different receptacle.

In another aspect of the invention there is a method of carrying outoperations on a plurality of items delivered at a first pitch, saidmethod comprising: i) performing a first operation on a plurality ofitems, each said first operation carried out by one of a plurality ofoperational member spaced at a said first pitch; ii) moving saidoperational members to a second pitch by moving one of said plurality ofoperational members with an actuating mechanism, said remainingplurality of said operational members being interconnected to said oneoperational member; iii) performing a second operation on said pluralityof items, each said second operation carried out by an operationalmember spaced at a second pitch.

In yet another aspect of the invention there is provided a method ofcarrying out operations on a plurality of items delivered at a firstpitch, said method comprising: i) performing a first operation on aplurality of items, each said first operation carried out by one of aplurality of operational member spaced at a said first pitch; ii) movingsaid plurality of operational members to a second pitch and dividingsaid plurality of operational members into at least two groups; iii)performing a second operation on said plurality of items, each saidsecond operation carried out by an operational member spaced at a secondpitch.

In another aspect of the invention there is provided an end effector foruse with a moving device, the end effector comprising: a) a frame havinga longitudinally elongated portion; b) a plurality of operationalmembers mounted to the elongated portion for longitudinal movement onthe elongated portion; c) an actuation mechanism mounted to the frameand directly connected to a first operational member of the plurality ofoperational members and operable to move the first operational memberlongitudinally from a first position to a second position, and from thesecond position to the first position; d) a linking apparatus forlinking longitudinally the first operational member to a secondoperational member of the plurality of operational members; wherein whenthe actuation mechanism moves the first operational memberlongitudinally from the first position to the second position, thesecond operational member is moved longitudinally by the linkingapparatus from a third position to a fourth position.

In yet another aspect of the invention there is provided a robot havinga robot arm with an end effector, the end effector comprising: a) aframe having a longitudinally elongated portion; b) a plurality ofoperational members mounted to the elongated portion for longitudinalmovement on the elongated portion; c) an actuation mechanism mounted tothe frame and directly connected to a first operational member of theplurality of operational members and operable to move the firstoperational member longitudinally from a first position to a secondposition, and from the second position to the first position; d) alinking apparatus for linking longitudinally the first operationalmember to a second operational member of the plurality of operationalmembers; wherein when the actuation mechanism moves the firstoperational member longitudinally from the first position to the secondposition, the second operational member is moved longitudinally by thelinking apparatus from a third position to a fourth position.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings illustrating by way of example only, embodiments of theinvention:

FIG. 1 a is a top view of a first embodiment of the end effector of thepresent invention with some parts omitted for clarity;

FIG. 1 b is a front elevation view in cross section at 1 b-1 b in FIG. 1a;

FIG. 1 c a side elevation view in cross section at 1 c-1 c in FIG. 1 a;

FIG. 1 d is a top perspective view of the end effector of FIG. 1 a, fromone side;

FIG. 2 is an exploded perspective view of part of the end effector ofFIG. 1 a;

FIG. 3 a is a bottom perspective view of the end effector of FIG. 1 a ina diverged configuration;

FIG. 3 b is a bottom perspective view of the end effector of FIG. 1 a ina converged configuration;

FIG. 4 is a bottom plan view of the end effector of FIG. 1 a, with pickup members removed for clarity, showing the linkage of the pick-upmembers;

FIG. 5 a is top perspective view of an end effector in accordance with asecond embodiment of the invention;

FIG. 5 b is a bottom perspective view of the end effector of FIG. 5 a;

FIG. 5 c is an exploded view of the end effector of FIG. 5 a;

FIG. 5 d is a view similar to FIG. 5 b showing the mounting of the camdisc;

FIGS. 6 a and 6 b are top perspective views of parts of the end effectorof FIGS. 5 a-5 c, which illustrate the actuation apparatus for the pickup members of the end effector of FIGS. 5 a-5 c;

FIG. 6 c is a schematic view showing the sequence of operation of partsof the end effector of FIGS. 5 a-5 c:

FIG. 7 is an exploded view of an end effector constructed in accordancewith a third embodiment of the invention;

FIGS. 8 a and 8 b are top perspective views of parts of the end effectorof FIG. 7, which illustrate the actuation apparatus for the pick upmembers of the end effector of FIG. 7;

FIG. 9 is top perspective view of an end effector in accordance with afourth embodiment of the invention;

FIG. 10 is a bottom perspective view of the end effector of FIG. 9;

FIG. 11 is top perspective view of an end effector in accordance with afourth embodiment of the invention

DETAILED DESCRIPTION

With reference to FIGS. 1 a-1 d, 2, 3 a and 3 b, and FIG. 4, an endeffector generally designated 20 is illustrated. Although not shown assuch in these Figures, in use end effector 20 is secured to a movingdevice such as the end of a robotic arm. End effector 20 is formed witha frame structure, to which a plurality of pick up members 30 aremovably attached. In this embodiment, the frame is made from two, spacedapart hollow rectangular pipe members 26 secured in a rigid,longitudinally parallel relation to each other by a main medial hubassembly 22. The pipes 26 and hub assembly 22 may in some embodiments bemade of a lightweight but durable material such as aluminum, or carbonfiber composites, fiber-glass, similar light composites and the like.Each of pipes 26 is sealed at its ends with closed plugs (not shown)such that the only openings to the interior of the pipes are thoseopenings which are connected to vacuum hoses, and a central opening tothe main vacuum manifold in the hub assembly, as will be describedhereinafter.

The overall path of vacuum air flow through end effector 20 is from thesuction cups 43, through the carrier members, into hoses 52, into andthrough one of pipes 26, and then through the passageway formed in hubassembly 22 to the external vacuum source.

As shown in FIGS. 1 a and 2, positioned longitudinally along the topface of each of the pipes 26 are holes or apertures 32. Holes 32 arepreferably positioned at equal distances from each other. As shown byway of example in FIG. 2, a hollow pipe connector plug 60 is fitted atone end into each of the holes 32. In some embodiments, the pipe plugs60 may be made of materials such as a plastic, suitable nylon, or othersuitable materials. The pipe connector plugs 60 are connected at theirother ends to flexible hoses 52. Flexible hoses 52 may in someembodiments be made of a flexible material such as a suitable rubber ornylon.

FIG. 2 provides an exploded top perspective view of parts of an endeffector 20 showing only one of the two pipes 26. As can be seen clearlyin FIGS. 1 c and 2, attached to the bottom face of each pipe 26 is alongitudinally extending guide rail 58. Each of the pick-up members 30used to lift items from a conveyor belt or some other location in thepackaging system are mounted on guide rails 58 and can slide along them.Each guide rail 58 is preferably shaped as a rectangular track with anarrow slot in its bottom face. Rail 58 extends across substantially theentire length of the bottom face of pipe 26. Each guide rail 58 may insome embodiments also be made of a light but durable metal material oralloy, such as aluminum.

Each of pick-up members 30 used to lift the items to be packaged issuspended from the rails 58 through the slot by rectangular platemembers 48 that can slide along the inside of guide rails 58. The platemembers 48 can be comprised of different components but include slidingportions that engage the rails that are preferably made from a materialthat facilitates easy sliding of the pick up member 30 in the rails 58,for example, materials such as polyethylene or teflon.

With reference in particular to FIGS. 1 b, 2, 3 a and 3 b the hubassembly 22 is mounted with side plates 36 to and between pipes 26,proximate the middle of each pipe 26. Like the other components fromwhich end effector 20 is assembled, side plates 36 are preferably madeof light but durable materials such as aluminum. Side plates haveapertures to reduce the weight. Side plates 36 can be mounted onto pipes26 by using conventional techniques such as screws that are insertedinto drilled holes 37 on side plates 36, which pass through the entirewidth of the side plates and fit into screw holes 38 (shown in FIG. 2)drilled onto the outside portion of pipe 26.

As shown in FIG. 2, the hub assembly 22, comprises a cylindrical pipe 63(preferably also made from a durable but lightweight material such as analuminum), that is connected to a manifold 61. The side openings ofmanifold 61 are sealed on either side with the side plates 36 which canbe fastened therein or glued in place, or attached in other conventionalways. The bottom plate 69 of manifold 61 has opposed side openings 67 atthe side edges of plate 69. Each opening 67 is mated with an opening 71in the top face of a pipe 26 and abuts with side plates 36. Thusmanifold 61 is sealed to pipes 26, with a substantially air tight sealsuch that air can flow from pipe 26 through openings 71 and 67 intomanifold 61 and can then pass through pipe 63 to the vacuum source. Ahose (not shown) connecting the vacuum source to pipe 63 can passthrough a cylindrical slot 70 that passes completely through the movableconnector member 24 that attaches the end effector 20 to the robot. Inthis way a vacuum can be applied to manifold 61 and pipes 26 to create asuction at suction cups.

The hub assembly is completed with a plate member 64 having anintegrally formed flange 66. Flange 66 is secured with screws to the topedge of plates 36 side through screw holes 59 and 57 (FIG. 2). Oncefastened to plates 36, plate member 64 contributes to the rigidity ofthe frame and provides a member to which movable connector member 24 ofa moving device can be attached. In particular, in the embodiment ofFIGS. 1 a-3 b, connector member 24 is configured for connecting endeffector 20 to the arm (not shown) of a Delta robot such as the onemanufactured by SIG Demaurex and used in their Presto packaging system,or the Delta robot manufactured by ABB Flexible Automation company andused with their IRB 340 FlexPicker packaging system. It will, of course,be appreciated that connection plate 24 can be configured for connectingend effector 20 to other types of robots. In the preferred embodiment,connector member 24 comprises a 3-legged flange that has ball bearings84 attached to each arm 68 a, 68 b, 68 c. Connector member 24 can besecured to plate member 64 in a conventional manner such as by screws.

FIGS. 1 b, 1 c, 3 a and 3 b illustrate a plurality of pick-up members 30associated with end effector 20. The pick-up members 30 are arrangedserially along a central longitudinal axis Y of end effector 20 (FIG. 3a). As shown in FIGS. 1 a, 1 b, 2, 3 a and 3 b, every pick-up member 30includes a carrier guide 40. It should be noted that in FIG. 2, thecarrier guides (exploded away from pipe 26) are formed in an H-sectionthat consists of a bridge section 44 and two side leg sections 42 thatare attached to either end of the bridge section, and extend above andbelow the bridge section. Carrier guide 40 is also shown in (FIGS. 1 cand 1 d) formed as being of a generally inverted C-shape, having sidelegs that extend only upwards from the bridge section. The H-shape ismore suitable when end effector is to be used for carrying heavierand/or larger items. Various other configurations are of coursepossible. Preferably, the carrier guide 40 is made of a suitable plasticmaterial such as a high density polyethylene, a suitable compositematerial, or some other equivalent light but durable material. Insertedinto a hole in the middle of the bridge section 44 of each H or C-shapedcarrier guide 40 is a pin formed from a hex-head shoulder screw 54. Thescrew 54 fastens the carrier guide 40 to a rectangular guide platemember 46.

Attached to each of the side edges of guide plates 46 are plates 48,each having outward extending flanges. Plates 48 are preferably madefrom a suitable plastic, and their flanges are received in the interiorof guide rails 58. The width of the flanges of plates 48 is larger thanthe width of the bottom slot of the guide rails or tracks 58 such thatthe plates 48 can slide longitudinally in the interior part of rails 58along the length of the rails, but cannot fall off from or out of theguide rails. When mounted onto rails 58 by fitting the plates 48 intothe interior section of guide rails 58 through the far ends of therails, each guide plate 46 can slide along at least a portion of thelength of the rails. Preferably, guide plate 46 is manufactured fromdurable materials such as aluminum, or possibly other durable materialsthat are relatively lightweight. In the preferred embodiment most of thesurface area of guide plate 46 is occupied by two elliptically-shapedslots which flank the middle part of guide plate 46. This configurationreduces the overall weight of guide plate 46. The middle part of theplate 46 includes a threaded bore into which hex-head shoulder screw 54is inserted to fasten the carrier 40 to the guide plate 46.

In both the embodiment shown in FIG. 2 and the embodiment in FIGS. 1 b,1 c, 3 a and 3 b, each carrier 40 has opposed upwardly extending legsections 42. Each leg section has a rectangular slot 41 passingvertically down to the base portion 44 of the leg 42 (as can be seen inthe exploded view of FIG. 2). A vertical bore is provided through legsection 42, with an upper opening at the bottom portion of the channel41, and a lower opening at the bottom surface of leg section 42.Attached proximate the bottom opening of each bore is a rubber suctioncup 43 with a small opening at the peak of the cup. A hollow tube 45 isfitted into the opening of suction cup 43. The tube 45 passes throughthe bore at the bottom of leg 42 and exits at the opening at the bottompart of slot 41. Each of tubes 45 (one passing through each bore in eachof legs 42) is in turn attached to a flexible hose 52, which, asexplained above, is attached to a pipe plug 60. The length of flexiblehose 52 should not limit the extent to which a pick-up member 30 canmove away from its respective pipe plug 60. As previously described, thepipe plugs 60 connect the flexible hoses to the hollow pipes 26, whichin turn attach to hub 22 and an extraneous vacuum source (not shown).Thus, when the vacuum source is turned on, a suction force is created atsuction cups 43 which causes items proximate cup 43 to be lifted andheld by the suction cups.

To control and facilitate the movement of the pick-up members 30, thepick-up members 30 that are mounted onto guide rails 58 areinter-connected to each other. In the preferred embodiment of thepresent invention, a pick-up member 30 is connected to an adjacentpick-up member 30 by using a tie link plate 50 as illustrated in FIGS. 2and 4. Tie link plate 50 is preferably a rectangular plate, made of aplastic such as polyethylene or some other light but durable material.Each pick up member 30 (except those pick up members at the end of theend effector) will be interconnected to a pick up member on each sidewith a link plate 50. Each link plate 50 will have one or more slotswhich receive therethrough pin or rod 54 associated with each pick upmember 30. Each pin or rod 54 is preferably made of steel, or some otherstrong wear resistant and good shear strength material, and ispreferably hollow so as to reduce the weight of the pin or rod. In thepreferred embodiment, each tie link 50 actually has two equallongitudinally extending slots 51, 53, each slot for receiving one pinof one pick up member 30.

A tie link plate 50 should be rigid enough that as a first pick-upmember to which the tie link is connected is forced in an outwarddirection from the center of the end effector 20, the second adjacentpick-up member 30 to which the tie link plate 50 is connected is pulledin the same direction. Tie links 50 are preferably formed by extrudingthe plastic, or some other material that meets the required criteria,through a mould bearing the shape of a tie link 50. Those skilled in theart will of course realize that a tie link 50 may be manufactured byother manufacturing processes. The length of the slots 51, 53 in a tielink 50 controls the extent to which adjacent pick-up members 30 can beseparated from each other. Generally, the larger the length of eachslot, the farther the possible separation that is possible between thepins and their respective pick up members.

Other tie links can also provide the desired functionality. For example,a tie link can be provided with only a single slot receiving two pinmembers. The tie link could also be constructed in other ways such aswith springs or rubber bands.

In the illustrated preferred embodiment, to link adjacent pick-upmembers, one slot of a tie link 50 is placed around the hex-headshoulder screw 54 of one pick-up member 30, while the other slot isplaced around the hex-head shoulder screw 54 of the adjacent pick-upmember 30. It will be apparent, that with the exception of the pick-upmembers 30 that are located at the far ends of the end effectorassembly, two tie links are placed around every hex-head shoulder screw,with each tie link 50 connecting a pick-up member 30 to the pick-upmembers 30 on one of its two sides. As shown in FIG. 4, the tie links 50are arranged in overlapping relationship. Once the tie links 50 areplaced on the hex-head shoulder screws 54 of the pick-up members, thescrews 54 can be fastened to the guide plate 46. As shown in FIG. 1 c,the tie links 50 are held above bridge sections 44 and below guideplates 46 between leg sections 42.

Thus, a chain of pick-up members 30 can be mounted onto guide rails 58by placing the plates 48, corresponding to one pick-up member 30,through the opening at the side of guide rails 58, sliding the pick-upmember 30 along the rails, and repeating the same for the other pick-upmembers 30. Once pick up members 30 are mounted on the rails, the end ofthe rails 58 could be sealed.

Control of the movement of the pick-up members 30 is achieved bycontrolling the movement of one, or more, pick-up member 30 using anactuation mechanism. Since all the pick-up members are interconnected toeach other through a chain of tie links 50, moving one leading pick-upmember 30 in a chain can cause the movement of other following pick-upmembers as well. In the preferred embodiment of FIGS. 1 a-4, two doubleacting pneumatic cylinders 28 a and 28 b are used to directly alter thepositions of the pick-up members 30 at the ends of the end effector 20.As best shown in FIG. 1 d cylinder 28 a (which is mounted andconstructed identically to cylinder 28 b) is connected to a compressedair source (not shown) through pipes connected to fittings 79 and 81. Abulkhead member 80 is fixedly attached to, and depends down from hubassembly 22. Cylinder 28 a is mounted between bulkhead member 80 andpick up member 30 a located at one end of end effector 30.

In one embodiment, industry standard double acting pneumatic cylinders,such as those manufactured by Festo, are used. As will be appreciated bythe person skilled in the art, in a double acting pneumatic cylinder,the piston in the cylinder can be pushed in two opposite directions,thereby allowing for the actuating rod attached to the piston to beeither extended or retracted. Cylinder 28 a can have its rod 31 a extendby forcing compressed air into fitting 81 and venting fitting 79. Rod 31b can be retracted by venting fitting 81 and applying compressed air tofitting 79. Compressed air is applied to fittings 79 and 81 with hoses(not shown), and venting takes place in known ways which can for exampleinclude a controller and valves, which can be integrated with theoverall control of the moving device.

Additionally it will be appreciated that cylinders 28 a and 28 b can becontrolled by for example a Programmable Logic Controller (“PLC”) (notshown) so that they work in unison. Therefore, they can have their rods31 a, 31 b extended and retracted at the same time.

The actuating rods 31 a and 31 b of pneumatic cylinders 28 a and 28 bpass in a longitudinally extending channel 33 (see FIG. 1 c) above thecarrier guides 46 of the pick up members. As shown in FIG. 2, theactuating rod 31 a of one pneumatic cylinder is fastened to plate 46 ofpick-up member 30 a using a clamp 29 and screws or bolts. The pneumaticcylinder 28 a and its rod 31 a are aligned so that the length of thecylinder 28 a and rod 31 a are oriented parallel to the length of pipes26.

In operation, the items that are to be packaged are positioned on aconveyor belt system or some other platform forming part of a packagingsystem. In the preferred embodiment, the end effector 20 is attached toa Delta robot. Optionally, the Delta robot may also include a sensorysystem, familiar to those versed in robotics, to determine the exactlocations of the items to be picked up and moved, and the distancesseparating them, so that the end effector 20 can be positionedaccordingly. It will however be typical for products only to be eitherpicked up or dropped off when the carrier members 30 are either fullydiverged or fully converged.

The control system of the Delta robot (not shown) positions the endeffector 20 attached to moving member 24 above the items to bepicked-up. Positioning of the end effector above the items to bepicked-up is done in ways known to those familiar in the art ofautomated and robotic system control. The control system controlling theoperation of the pneumatic cylinders 28 a and 28 b then releasescompressed air that causes the pistons of the pneumatic cylinders 28 aand 28 b, to extend the actuating rods 31 a and 31 b to a desiredposition, so that the pickup members 30 are situated above the items tobe picked-up. The control system of the robot also will position the endeffector as a whole (i.e. move the frame) to the correct position.Control of the pneumatic cylinders 28 a and 28 b and the extension ofthe actuating rods is done in ways known to those versed in the art ofpneumatic cylinder control, such as by having valve operation controlledby a PLC or the robot's controller.

With reference to FIG. 4, the actuation of the pick-up members 30attached to pneumatic cylinders is shown. When the actuating rod 31 aattached to the pneumatic cylinders 28 a is extended, the pick-up member30 a at the far end of one side of the end effector is extendedoutwardly and away from the center of the end effector. The hex-headshoulder screws 54 a of the far end pick-up member 30 a starts movingoutwardly in the slot 51 a of the tie link 50 a in which the screw 54 ais placed until it starts pressing against the outer side of the opening51 a in tie link 50 a. This in turn causes the tie link 50 a to bepushed outwardly, thus causing the side edge of opening 53 a in tielinks 50 a to push against the hex-head shoulder screws 54 b of theadjacent pick-up member 30 b. This causes pick-up member 30 b to also bepulled outwardly and away from the center hub assembly 22 of endeffector 20. The other pick-up members 30 inter-linked to pick-up member30 a will also be pulled outwardly and away from the center of the endeffector 20. Similarly, the same effect is achieved on the other side ofhub assembly 22 when actuating rod 31 b attached to the piston ofpneumatic cylinder 28 b extends outwardly, but in a direction oppositethat in which the actuating rod 31 a and pick-up member 30 a is moved.The result is that when the cylinders are fully extended, the pick upmembers 30 are configured as shown in FIG. 3 a, with the pins (screws54) being positioned at the outer edges of the slots in tie links 50 (asshown in FIG. 4).

It will be appreciated that in this embodiment, if the actuating rods 31a and 31 b are extended by less than their maximum extension, separationbetween the pick-up members 30 will be non-uniform since the partialextension of the pick-up members at the far ends of the end effector 20may not be enough to cause the tie links 50 linked to the pick-upmembers closer to the center of the end effector to push those pick-upmembers outwardly. Therefore, where the actuating rods 31 a and 31 b arenot fully extended, the pick-up members will be more closely clusteredor spaced near the center of the end effector 20.

Once the pick-up members 30 are positioned exactly above the items to bepicked-up, the end effector is lowered so that the suction cups 43attached to each carrier guide 40 of each pick-up member 30 are broughtinto contact with the items to be picked-up. The vacuum source attachedto the Delta robot will then be activated (if it has not already beenactivated) thereby creating a suction force at the suction cups 43. Thiscauses the items on a conveyor belt (not shown), or other platform onwhich the items are located, to be lifted off the conveyor belt, andheld by the suction cups 43.

The Delta robot next moves the moving member 24, and the end effector 20connected to it, in the direction of the receptacle where the items areto be deposited. The position and orientation of the end effector iscontrolled by the arm sections of the Delta robot. While the endeffector 20 moves towards the destination receptacle, the actuating rods31 a and 31 b can start retracting by having compressed air from thecompressed air source applied to, and corresponding venting of thefittings of the pneumatic cylinders 28 a and 28 b so that the pistonsare moved back into their retracted positions. This in turn causes thepick-up members 30 on either side of the central portion, to convergeback toward the center of the end effector 20, to the position shown inFIG. 3 b. This enables the items carried by the end effector 20 to bedeposited into the receptacle (not shown). The extent of the desiredconvergence of the pick-up members 30 will depend on the size of thereceptacle into which the lifted items are to be deposited. A receptaclewith a relatively small opening will require that the pick-up members 30be more tightly converged.

The extent to which the cylinders can retract and compress pick upmembers 30, will be determined by the movement of the rods, theconfiguration of the slots in the tie links 50, and the physical sizeand shape of the pick up members themselves. It is usually desired thatthe 30 members be able to be compressed until they are in abutment witheach other as shown in FIG. 3 b, so that in fully converged position,the pins of the end effectors are not in abutment with the inside facesof the slots 51 and 53. However in other embodiments, the tie linksthemselves, and in particular the configuration of the slots 51 and 53,can be selected so that during the contraction, the tie links innerfaces interact with the pins to push the members together and thisdetermines the minimum separation of members 30.

Once the end effector 20 reaches a position directly above thedestination receptacle, the end effector 20 is lowered into thereceptacle. The suction force at suction cups 43, created by the vacuumsource, is cut off, thereby releasing the items from the suction cups43. The end effector is then raised, and the Delta robot can then movethe end effector 20 to a position above the next batch of items to bepackaged. The destination receptacle into which the items were depositedis, meanwhile, further processed by the packaging system.

One disadvantage of using pneumatic cylinders to actuate the position ofthe pick-up members is that pneumatic cylinders have non-linear behaviordue to the use of compressed air as the means of controlling theposition of the pistons in the cylinders. This leads to poor control ofthe speed and precise position of the pistons. Accordingly, in thesecond embodiment of the present invention an end effector isimplemented with a more precise actuation mechanism.

With reference to FIGS. 5 a, 5 b and 5 c an end effector 120 is shown,and which is constructed in a manner similar to end effector 20. Endeffector 120 comprises of two hollow rectangular pipes 126 that are openat their far ends. Pipes 126 are configured in a parallel longitudinalarrangement. A pipe cap 132 is inserted into each of the openings at thefar ends of the pipes, thus sealing the pipes 126 at their ends. Fittedinto holes 121 located on the top surface of the pipes 126 along themain axis of the pipes 126 are connector pipe plugs 134. Connected toeach pipe plug 134 is one end of a flexible hose 136 (for clarity in thefigures, only one such hose 136 is shown, in FIG. 5 c) made of flexible,and preferably resilient material, such as rubber.

Each hose 136 is attached at its opposite end to a hollow connector tube147 (like tubes 45 in the previous embodiment). The tube 147 is receivedinside the bore on one of the legs 142 of a pick-up member 130. Thepick-up members 130 used in this embodiment of the end effector of thepresent invention are substantially the same pick up member 30 as thosedescribed in relation to the first embodiment of the end effector. Aswill become apparent below, because the actuation mechanism used inconjunction with the second embodiment of the end effector is bulkierand occupies more space than the actuation mechanism used with the firstembodiment of the end effector, it is more expedient to pass theflexible hoses 136 on the outer sides of the hollow pipes 126 than fromthe inner sides of the pipes. Furthermore, to allow for easy attachmentof the flexible hoses 136 to hollow connector tubes 147, a generallyC-shaped tube can be used.

A hose 136 also extends from a pipe plug 134 on the opposite, secondhollow pipe 126, positioned across from the first pipe plug, andattaches to the hollow connector tube 145 received inside the bore onthe other leg of the same pick-up member 130. Accordingly, every pick-upmember 130 is attached to two with connectors 147 to two flexible hoses136, one extending from each of the hollow pipes 126.

Each pipe 126 also consists of two inner side openings 123 locatedproximate to the ends of the pipes 126. Each opening extends inwardlyfrom the middle of the top side of each pipe 126 towards the center ofthe end effector down to the middle of the inner side of each pipe. Theopenings on one pipe 126 are positioned opposite and across from theopenings on the other pipe 126.

Two hollow, generally T-shaped header manifold assemblies 131 areprovided at opposite end of the pipes 126 in between the side openings123 on each pipe 126, thereby completely covering and substantiallysealing the openings 123 in the pipes 126. Manifold assemblies 133 haveside plate members 133 which complete the side seals. A circular bore isprovided in the top surface of each of the T-shaped header manifoldassemblies 131, and a cylindrical pipe 138 is fitted into the bores.Connected to each of the cylindrical pipes 138 is one end of a hose (notshown), that is in turn connected at its other end to an extraneousvacuum source (not shown). The suction cups 143 on each of the pick-upmembers 130 are therefore interconnected to the vacuum source throughthe hollow tubes 145, which are connected to flexible hoses 136, thatare connected to the pipe plugs 134, that are fitted into the hollowpipes 126 and which in turn are connected to the T-shaped manifoldassemblies 131, that are connected to cylindrical pipes 138, which arein communication with the vacuum source. Consequently, when the vacuumsource is turned on, a suction force is created at the suction cups 143,thereby lifting and holding items to be packaged when they are locatedproximate suctions cups 143. Of course, it will be appreciated that adifferent gripping mechanism may be employed to lift and transfer theitems to theft destination receptacles instead of the vacuum basedmechanism used in this embodiment.

Attached to the bottom of each pipe 126 is guide rail 158. As with endeffector 20, each guide rail 158 of end effector 120 is preferably alsoa hollow rectangular pipe with a narrow opening at the bottom surface ofthe pipe extending longitudinally along the entire length of guide rail158. Mounted on the guide rails 158 are pick-up members 130. The pick-upmembers 130 are linked to each other using the tie link 50 mechanismdescribed above. Each tie link 50 links together two adjacent pick-upmembers 130 by placing the hex-head shoulder screw 54 of one of thepick-up members 130 through one slot of the tie link 50, and placing thehex-head shoulder screw of the adjacent pick-up member 130 through theother slot of the tie link. The chain of pick-up members 130 is thenmounted onto guide rails 158 by fitting the plates 156 attached to thesliding carrier guide 46 of each of the pick-up members through theopening at the far ends of the guide rail 158, and sliding the pick-upmembers down the guide rails 158.

Mounted on the upper surface of each of pipe 126, at a medial position,is a side plate 136. Hub assembly 122, comprising of a cylindrical hubportion 164 and a flange 166, is then fastened to the side plates byusing screws 165 to attach the flange 166 to top edges of side plates136. Fitted within the cylindrical hub portion 164 of hub 122 andbearing mounted on robot connection member 124 of the robot, is a rotarycam device 172. Rotary cam 172 is a circular disc having cam followers174 a, 174 b which interact with cam tracks in cam blocks to provide cammovement to effect the actuation of the pick-up members 130 of the endeffector 120.

Pipes 126, manifold assemblies 131, side plates 136, rotary cam disc172, hub portion 164 and flange plate 166 can all be made fromlightweight but durable materials such as, for example, aluminum.

The cam followers 174 a, 174 b are small knobs or pins positioneddiametrically opposite to each other on disc 172 proximate the perimeterof the bottom surface of rotary cam 172. As will become apparent below,the cam followers 174 a, 174 b engage the actuation mechanism of the endeffector 120 and control the outward expansion or convergence of pick-upmembers 130.

The rotary cam 172 can be bearing mounted to moving connector member 124of a Delta robot using a cross nut or other conventional mountingmechanisms. Cam disc 172 is secured to the end of a shaft 198 thatextends through a slot 170 in member 124. Moving member 124, much likemoving member 24 of the first embodiment of the present invention, isthe part of the Delta robot that moves about in a three-dimensionalspace. Moving member 124 comprises of a 3-legged shaped flange 168, atthe middle of which, is a threaded cylindrical slot 170. A rotatableshaft (not shown) extending from the Delta robot is fitted into slot 170and attaches to a shaft connector 178 which in turn is connected toshaft 198. The rotatable shaft of the Delta robot is connected to amotor (not shown) that controls the rotation of the shaft. Rotation ofthe robots shaft thus causes shaft connector 178 to rotate. This causesshaft 198 to rotate and thus rotary cam 172 to rotate clockwise, orcounter-clockwise so as to control the actuation of the pick-up members30.

To secure end effector 120 to the robot arm, screws 199 are used,passing through holes 197 in flange 168 to attach in holes 199(typically only three are needed) of hub portion 166. This connects hubassembly 122 to the underside of connector member 124.

Hub assembly 122 (1) produces structured rigidity to the frame of theend effector (2) provides a securement mechanism for mounting effector120 to the robot through attachment to connector member 124 and (3)provides rigidity to resist the forces imparted during rotating of camdisc 172 which moves cam blocks 144.

The actuation mechanism 140 that interacts with the cam followers 174 a,174 b comprises of two cam slider blocks 144 a and 144 b, each can bemade of a plastic such as for example, polyethylene or of a comparablelightweight and durable material. Each cam block has two transverselyoriented, spaced cam slots 146 a, 147 a and 146 b, 147 b that are formedin top surfaces of each of the cam blocks.

Extending from each side of each cam block 144 a, 144 b are rod members.Thus cam block 144 a has rod 142 a extending longitudinally from one ofits sides and which is clamped at its end to a pick-up member 130 usinga clamp 148. The pick-up member 30 to which the push rod 142 a isclamped is the pick-up members situated at the far end of the endeffector. That is, push rod 142 a of cam block 144 a is attached to thefar end pick-up member 130 a at one end of the end effector. Push rod142 a at its other end is attached to a cam block 144 a. Attached to theother side of each of cam block 144 a is rod 145 a. Rod 145 a is notclamped to any pick-up member but is merely used to properly guide themovement of cam block 144 a, and to prevent the cam block 144 a fromwobbling while being engaged by the rotary cam 172.

Likewise, cam block 144 b has rod 142 b extending longitudinally fromone of its sides (on the opposite side to rod 142 a) and which isclamped at its end to a pick-up member 130 b using another clamp 148.The pick-up member 130 to which the rod 142 b is clamped is the pick-upmembers situated at the far end of the end effector, opposite to thepick up member to which rod 142 a is attached. Rod 142 b at its otherend is attached to a cam block 144 b. Attached to the other side of camblock 144 b is rod 145 b. Rod 145 b is not clamped to any pick-up memberbut is merely used to properly guide the movement of cam block 144 b,and to prevent the cam block 144 b from wobbling while being engaged bythe rotary cam 172.

The cam blocks 144 a, 144 b and the rods attached to them are positionedbetween the two hollow pipes 126. The actuation mechanism is secured tothe hollow pipes 126 by using two plastic T-shaped bearing plates 150 aand 150 b. Each T-shaped bearing plate is fixed to the hollow pipes 126by fastening the arms extending from the top of the bearing plate to thehollow pipes 126 using screws. Preferably, each T-shaped bearing plateis positioned on either side of the side plates 136, between the sideplates and the first set of pipe plugs 134 immediately next to the sideplate. Each bearing plate 150 a and 150 b also consists of two aperturessituated near the bottom of, and transversely spaced on the plate. Asbetter seen in FIGS. 6 a and 6 b, rod 145 a of cam block 144 a passesthrough one hole in bearing plate 150 a, while push rod 142 b of camblock 144 b passes through the other adjacent hole in plate 150 a.Likewise, rod 145 b of cam block 144 b passes through one hole inbearing plate 150 b, while rod 142 a of cam block 144 a passes throughthe other adjacent hole in plate 150 b. This arrangement of two rodsattached to every cam block and having the rods passing through holes intwo bearing plates that are rigidly secured to the pipes 126 allows thecam blocks to maintain stability without wobbling. Additionally, block144 a, can move longitudinally and pass by block 144 b in close orabutting relation thereto.

FIGS. 6 a and 6 b illustrate the operation of the actuation mechanism ofthe second embodiment of the end effector 120. FIG. 6 b shows the twosliding cam blocks 144 a and 144 b, in their mid positions relative tothe end effector. At that position, the two cam blocks are aligned sothat the two blocks are at the same longitudinal position. Additionally,in the mid-point position the cam followers 174 are positioned insidethe slots 146 a and 146 b of both cam blocks 144 a and 144 b,effectively straddling both cam blocks. As can be appreciated from themid-position drawing of FIG. 6 b, the separation between the slots 146and 147 of each cam block as measured from the interior walls of eachslot has to be slightly smaller than the diameter of the rotary cam 172so that the cam followers 174 a, 174 b could be properly placed insidethe slots at the mid-point position.

Starting from the position shown in FIG. 6 a, the movement of camfollowers 174 a, 174 b in the slots in the cam blocks 144 a, 144 b isshown in FIG. 6 c, As the rotary cam 172 begins to rotate counterclockwise from 0 degrees, one cam follower moves outward in slot 147 aof cam block 144 a, while the other cam follower moves outward in slot147 b of cam block 144 b. As the rotary cam rotates, the cam followerinside slot 147 b of cam block 144 b exerts pressure on the wall of slot147 b, thereby pushing cam block 144 b toward the center of the endeffector. Consequently, pick-up member 30 a, clamped to rod 142 b of camblock 144 b, converges toward the center of end effector 120. The sameeffect is achieved by the movement of cam block 144 a and rod 142 a,likewise converging the pick up member to which it is attached towardthe center.

The movement of the cam followers and cam blocks continues as shown inFIGS. 6 a-6 c, with the rotation of rotary disc 172 and the accompanyingmovement of the cam followers. When the cam followers reach the positionshown in FIG. 6 c as 360 degrees the pick up members will be in theirfully converged position.

By reversing the direction of rotation of the shaft to which the camfollowers are attached, the pick up members to which rods 142 a, and 142b are attached can be extended outward away from the central hubassembly. Since all the pick-up members 130 mounted on end effector 120are inter-linked to each other by tie links 50, at the fully extendedposition of the cam blocks 144 a and 144 b, all the other pick-upmembers mounted on end effector 120 will reach their fully extendedposition.

In operation, the control system controlling the Delta robot positionsthe end effector 120 coupled to the moving member 124 above the itemsthat are to be packaged. Optionally, a sensory system may be used todetermine the exact locations of the items on the conveyor belt or otherplatform on the packaging system, so that the end effector could bepositioned accordingly. The rotary cam is then rotated clockwise toextend the far end pick-up members clamped to the pushing rods attachedto each cam block, thereby extending the pick-up members linked orinter-linked to the far end pick-up members through tie links 50. Thepick-up members 130 are extended until they are situated directly abovethe items that are to be packaged. Subsequently, the end effector 120 islowered so that the suction cups 143 attached to the H-carrier guide ofeach of the pick-up members 130 touch the items to be picked-up. Thevacuum source interconnected to the suction cups is turned on, therebycreating a suction force at the suction cups 143, which causes the itemsto be packaged to be lifted and held by the suction cups.

The Delta robot next moves the end effector 120 in the direction of thereceptacle where the items are to be deposited. The position of the endeffector 120 is controlled by the non-jointed arm sections of the Deltarobot, while the orientation of the end effector about the z-axis iscontrolled by the rotatable shaft of the Delta robot inserted into slot170 on moving member 124. Preferably, while the end effector is en-routeto the receptacle, the control mechanism of rotary cam 172 begins torotate the rotary cam counter-clockwise, thereby causing the push rods142 a and 142 b of the respective cam blocks 144 a and 144 b to beretracted back to the center of the end effector. This in turn causesthe pick-up members 130 to converge back to the center of the endeffector, thereby allowing the picked-up items to be easily depositedinto the destination receptacle.

Once the end effector 120 reaches a position directly above thereceptacle, the end effector is lowered until the items are placedinside the destination receptacle. Subsequently, the vacuum source iscut off, thereby releasing the items from the grip of the suction cups143. The end effector is then raised above the top opening of thereceptacles, and is repositioned by the Delta robot to pick-up the nextbatch of items.

It will be appreciated that the system could be used in an oppositeconfiguration, whereby items are picked up at a first location in aclose, converged arrangement. The items can then be diverged prior todelivery to a second location.

FIGS. 7, 8 a and 8 b show a third embodiment of an end effector of thepresent invention, which enables the end effector to pick up severalitems and then separate those items into discrete groups. This isaccomplished by providing an end effector where the pick-up membersmounted for moving items into discrete groups. Each group can then, forexample, be simultaneously deposited into separate destinationreceptacles. This allows for more efficient and controlled packaging ofthe items. To provide an end effector with pick-up members that candivide items into discrete groups, a modified implementation of theactuation mechanism described in the second embodiment is employed, butthe end effector is otherwise substantially the same as the end effectorof FIGS. 5 a-5 c.

End effector 220, shown substantially dismantled in FIGS. 7 and 8 a, hasspaced, pipe members 226 with end flange assemblies 231 secured theretoand vacuum connection tubes 238. Carrier members 230 a-230 j are mountedto rails attached to pipe members 226 as described above.

Unlike the actuation mechanism used in conjunction with the secondembodiment, the actuation mechanism of the third embodiment of the endeffector 220, comprises of a single cam block 244. Cam block 244 is arectangular block, may in some embodiments be made of a suitable plasticsuch as for example, polyethylene, or another light but durablematerial, in which a single cam slot 246 is cut out of, or formed in,the top part of the block along the entire width of the block. The widthof the slot preferably approximates the diameter of a circular camfollower 274 protruding from the bottom surface of rotary cam 272. Thisallows the cam follower to fit inside the slot, and to press against thewalls of the slot as soon as the rotary cam starts rotating clockwise orcounter-clockwise, thereby pushing the cam block in either direction ofthe longitudinal axis of the end effector. Specifically, with referenceto FIGS. 8 a, 8 b, when the carriers 230 a-230 j are in the divergedposition shown in FIG. 8 a, and then when rotary cam 272 is rotatedclockwise, the cam follower presses against the wall on the right-handside of the slot, and causes the cam block 244 to move to the right. Onthe other hand, when the rotary cam rotates counter-clockwise, (or ifthe cam follower is rotated past 180 degrees) the cam follower 274presses against the wall on the left-hand side of the slot 246, andaccordingly causes the cam block to move to the left.

It should be noted that in this embodiment the rotary cam 272 can beoperated in only one direction (i.e. clockwise or counterclockwise)through the full 360° to achieve the full cycle ofconvergence-divergence-convergence or divergence-convergence-divergenceof the carrier members.

A long push rod 242 d is positioned between pipes 226 and is attached toone side of the cam block. A short rod 242 a is also positioned betweenpipes 226 and attached on the other side of cam block 244. Both rods 242a, 242 d move in the same direction as cam block 244 moves. It should benoted that rotary cam 272, used in conjunction with end effector 220,consists of only one cam follower, in contrast to cam rotary 172 used inconjunction with end effector 120 which has two cam followers that eachsimultaneously engage one of the two cam blocks.

FIGS. 8 a and 8 b shows the implementation and operation of the thirdembodiment of the present invention whereby the ten pick-up members orcarriers mounted on the end effector 220 can be separated into twogroups, each consisting of five pick-up members. As can be seen in FIGS.8 a and 8 b, pick-up member 230 a is clamped to rod 242 d, while pick-upmember 230 f is clamped to rod 242 a. To effect a separation of thepick-up members into two groups, pick-up member 230 e and pick-up member230 j have to be fixed to the end effector, preferably by securing thosetwo pick-up members to guide rails 158 or to the hollow pipes 226 usingscrews, in a manner described above. Pick-up members 230 a-230 e areinter-linked to each other by placing tie links 50 around the hex-headshoulder screws of adjacent pick-up members, as described above. Pick-upmember 230 e, however, is not linked to pick-up member 230 f. Similarlypick-up members 230 f-230 j are inter-linked to each other using tielinks 50, in a manner as described above. As will be appreciated, fixingpick-up members 230 e and 230 j to the end effector also serves toconstrain the maximum outwardly extension of rods 242 d and 242 b. Sincepick-up member 230 e is inter-linked to pick-up member 230 a, pick-upmember 230 a can only be moved to a maximum distance equivalent to thelength permitted by 4 tie links 50 from pick-up member 230 e. Similarly,since pick-up member 230 j is inter-linked to pick-up member 230 f,pick-up member 230 f can only be moved to a distance equivalent to thelength permitted by 4 tie links 50 from pick-up member 230 j.

As shown in FIG. 8 a, the pick-up members 230 are positioned in theirexpanded state. When the rotary cam 272 is subsequently rotatedcounter-clockwise, as is shown in FIG. 8 b, the cam block 244 is pushedto the right. Consequently, pushing rod 242 d starts moving to theright, pushing in the process the pick-up members 230 a-230 e linked toit. However, because pick-up member 230 e is fixed to the end effector,pick-up members 230 a-230 e converge to each other, thus forming asingle group of five pick-up members 230 a-230 e. Similarly, pushing rod242 a is also pushed to the right, causing the pick-up member 230 f, towhich the pushing rod 242 a is clamped, to also move to the right. Inthe process, pick-up members 230 g-230 i are also pushed to the right.Because pick-up member 230 j is fixed to the frame of the end effector(such as to pipes 226), the pick-up members 230 f-230 j converge into asecond group of pick-up members.

It will be appreciated that if it desirable to separate the pick-upmembers into other size groups, for example five groups consisting eachof two pick-up members, then it is necessary to clamp pick-up members230 a, 230 c, 230 e, 230 g, and 230 i to one of pushing rods 242 d or242 a, and fix pick-up members 230 b, 230 d, 230 f, 230 h, and 230 j tothe frame of end effector 220 (such as pipes 226).

In operation, the control system controlling the Delta robot positionsthe end effector 220 coupled to the moving member 224 above the itemsthat are to be picked up. Optionally, a sensory system may be used todetermine the exact locations of the items on the conveyor belt or otherplatform on the packaging system, so that the end effector could bepositioned accordingly. The rotary cam 272 is then rotated clockwise tomove the pick-up members into their expanded position shown in FIG. 8 a.Rotation of the rotary cam 272 is effected by a rotatable shaft (notshown) extending from the Delta robot and inserted into through aperture270 on moving member 224. The pick-up members 230 a-230 j are extendeduntil they are situated directly above the items that are to bepicked-up. Subsequently, the end effector 220 is lowered so that thesuction cups 243 attached to the C-carrier guide of each of the pick-upmembers 230 a-230 j touch the items to be packaged. The extraneousvacuum source—interconnected to the suction cups 243 through thecylindrical pipes 238, the hollow pipes 226, the plug pipes 134, theflexible hoses 236 and the hollow tubes 45—is engaged, thereby creatinga suction force at suction cups 243, which causes the items to be liftedoff and held by the suction cups.

The Delta robot next moves the end effector 220 in the direction of thedestination receptacles where the items are to be deposited. Theposition of the end effector 220 is controlled by the non-jointed armsection of the Delta robot. Preferably, while the end effector isen-route to the destination receptacles, the control mechanism of rotarycam 272 begins to rotate the rotary cam counter-clockwise, therebycausing the push rods 242 a and 242 b to move to the right. This in turncauses the pick-up members 230 a-230 e to converge into one group ofpick-up members, and converge pick-up members 230 f-230 j into anothergroup of pick-up members.

Once the end effector 220 reaches a position directly above the twodestination receptacles, the end effector is lowered until the itemslifted by one group of pick-up members are placed inside one destinationreceptacle, while the other items lifted by the other group of pick-upmembers are placed inside the other destination receptacle.Subsequently, the vacuum source is cut off, thereby releasing thearticles from the grip of the suction cups 243. The end effector is thenraised above the top opening of the receptacles, and is repositioned bythe Delta robot to pick-up the next batch of items to be packaged.

In FIGS. 9 and 10, an end effector 420 that is a variation of theembodiment of FIGS. 7-8 b is shown, along with the arms from a robotarm. In this embodiment, an end effector 420 is constructed like endeffector 220 but is made with only a single central pipe member 426.Pipe member 426 has a single rail 458 extending along its lower face anda total of eight pick up members 430 with suction cups 423 are securedfor sliding movement thereon. Vacuum is supplied through pipes 438 tosealed pipe 426, through hoses 436 into carriers 430 and suction cups423. Pick up members 430 a, 430 e, 430 f and 430 j are configured like230 a, 230 e, 230 f and 230 j in FIGS. 8 a, 8 b and are interconnectedwith carriers 430 b, 430 c, 430 g, 430 j, to effect movement that is thesame as in that embodiment of FIGS. 8 a and 8 b. In the embodiment ofFIGS. 9 and 10, rods 428 d, and 428 a connected to cam block 444 areprovided on both sides of pipe 426 to ensure free sliding of pick upmembers 430 on rails 458.

Finally, another embodiment is shown in FIG. 11 in which an end effectorgenerally designated 520 is illustrated. Although not shown in FIG. 11in use end effector 520 is secured to a moving device such as the end ofa robotic arm. End effector 520 is formed with a frame structure, towhich a plurality of pick up members 530 a-k are movably attached asdescribed above. In this embodiment, the frame is made from a single,hollow rectangular pipe member 526. As with the other embodiments, thepipe 526 and hub assembly 522 are preferably made of a lightweight butdurable material such as aluminum, or carbon fiber composites, orsimilar light composites. Pipe 526 is sealed at its ends with closedplugs (not shown) such that the only openings to the interior of thepipes are those openings which are connected to vacuum hoses withconnectors 560, and end pipes 538.

The overall path of vacuum air flow through end effector 520 is from thesuction cups (not shown), through the carrier members 530, viaconnectors 545 into hoses 552, through side connectors 560 on side 526 aof pipe. The positioning of hoses 552 can reduce the wear that the hosesmight encounter when during movement of the effector, they interact orrub against other parts of the robot arm. From pipe 526 air is drawnthrough pipes 538 to the external vacuum source.

The hub assembly 522 is mounted with transversely oriented side plates336 to pipe 526, proximate the middle of the pipe 526. Like the othercomponents from which end effector 520 is assembled, side plates 536 arepreferably made of light but durable materials such as aluminum.

Extending between and secured at ends to, plates 536 on both sides ofpipe 526, are cam block support rods 590. Each rod 590 supports one ofcam blocks 544 a, 544 b for sliding longitudinal movement thereon. Camblock 544 a has secured to it, one end of cam rod 542 a, which isattached at its other end, to carrier 530 a. Cam block 544 b has securedto it, one end of cam rod (not shown but which is the same as rod 542 a)which is attached at its other end, to carrier 530 k.

Rotary cam disc 572, which is generally mounted and driven as describedabove and being interconnected to a rotating power source with shaft578. As described above, rotary cam 572 can be mounted to a movingconnector member 524 of a Delta robot. Disc 572 has a pair of camfollowers 574 positioned 180 degrees apart on the periphery of the disc572, each engaging one of the cam blocks 544.

To control and facilitate the movement of the pick-up members 530, allthe pick-up members 530 a-k are interconnected in a chain like manner asdescribed above with tie links. All members 530 a-k are free to movealong the guide rail 558, but it should particularly noted thatcentrally located carriers 530 e and 530 f will have their movement inan outward direction constrained by the tie link between them, and theirinward movement by the tie link or the actual carrier themselves.

Control of the movement of the pick-up members 530 is achieved bydirectly controlling the movement of pick-up members 530 a and 530 kusing the actuation mechanism comprising the rotary disc 572, camfollowers 574, cam blocks 544 and rods 542.

In FIG. 11, carriers 530 are shown in the diverged configuration withcam followers 574 in the approximately 3 o'clock and 9 o'clock position.By rotating cam disc 572 about 180 degrees or perhaps slightly less, ina counter clockwise direction from the position shown in FIG. 11, camblocks 544 will be moved toward and past the center of pipe 526, thuspulling carrier members 530 a and 530 k to converge with other carriermembers in the chain toward fixed carrier members 530 e, 530 f, andtoward a central position, in a manner like that described above. Whenfully converged, all carrier members 530 a-k can be in abutment witheach other. Alternatively, the inward movement can be constrained by theconfiguration of the tie links. By reversing the direction of movementof cam disc 572 to rotate about 180 degrees in a clockwise direction thecarrier members can be returned to the diverged position shown in FIG.11.

These and other modifications and variations will readily becomeapparent to those of ordinary skill in the art without departing fromthe scope of the invention. For example, although in the embodimentsshown herein, tie links between carriers are shown each of the sameconfiguration, it is possible to vary the configuration of some of thetie links so that there are different configurations used. This couldprovide for non-constant spacing between the carrier members in theconverged and/or diverged positions.

I claim:
 1. An end effector for use with a moving device, said endeffector comprising: a) a frame; b) a plurality of operational membersmounted for longitudinal movement on said frame; c) an actuationmechanism directly connected to a first operational member of saidplurality of operational members and operable to move said firstoperational member from a first position to a second position in, d) alinking apparatus for linking said first operational member to a secondoperational member of said plurality of operational members said secondoperational member not directly connected to said actuation mechanism;wherein when said actuation mechanism moves said first operationalmember from said first position to said second position, said secondoperational member is moved by said linking apparatus from a thirdposition to a fourth position; and wherein said actuation mechanismcomprises: i) at least one cam block having a cam slot in an uppersurface of said cam block said cam slot extending in a generallytransverse direction that is generally orthogonal to the direction oflongitudinal movement and across said upper surface of said cam block,said cam block also being mounted for longitudinal movement relative tosaid frame; ii) a generally longitudinally oriented member attached tosaid cam block and to said first operational member; iii) a rotary cammounted and operable for rotation about an axis that is generallyorthogonal to said direction of longitudinal movement and saidtransverse direction, said rotary cam having at least one cam followerprotruding from said rotary cam, wherein said at least one cam followeris positioned to move transversely inside said cam slot of said camblock and move said cam block in a longitudinal direction duringrotation of said rotary cam.
 2. An end effector as claimed in claim 1wherein said actuation mechanism is directly connected to a thirdoperational member of said plurality of operational members and isoperable to move said third operational member from a fifth position toa sixth position, and from said sixth position to said fifth position,said linking apparatus also for linking said third operational member toa fourth operational member of said plurality of operational members;and wherein when said actuation mechanism moves said third operationalmember from said fifth position to said sixth position, said fourthoperational member is moved by said linking apparatus from a seventhposition to an eighth position; and wherein said at least one cam blockcomprises: a) a first cam block having a first cam slot in an uppersurface of said first cam block extending generally in said transversedirection across said upper surface of said first cam block, said firstcam block being mounted for longitudinal movement relative to saidframe; b) a second cam block having a second cam slot in an uppersurface of said second cam block extending generally in said transversedirection across said upper surface of said second cam block, saidsecond cam block being positioned in parallel longitudinal relation tosaid first cam block and being mounted for longitudinal movementrelative to said frame; and wherein said actuation mechanism furthercomprises: a first rod attached to said first cam block and to saidfirst operational member; ii) a second rod attached to said second camblock and said third operational member; and wherein said rotary cam hasa first cam follower protruding from said rotary cam and wherein saidfirst cam follower is positioned to move transversely inside said firstcam slot of said first cam block and push said first cam block in afirst direction during rotation of said rotary cam in a first rotationaldirection, and said rotary cam having a second cam follower protrudingfrom said rotary cam, wherein said second cam follower is positioned tomove transversely inside said second cam slot of said second cam blockand push said second cam block in a direction opposite to said firstdirection during rotation of said rotary cam in said first rotationaldirection about said axis.
 3. An end effector as claimed in claim 2further comprising a rotatable shaft for driving said rotary cam aboutsaid vertical axis, and wherein said rotatable shaft is driven by amotor associated with said moving device.
 4. An end effector as claimedin claim 3 further comprising a controller for controlling the motor andthus the rotation of said rotatable shaft.
 5. An end effector as claimedin claim 2 wherein when said actuation mechanism moves said firstoperational member from said second position to said first position,said second operational member is moved by said linking apparatus fromsaid fourth position to said third position.
 6. An end effector asclaimed in claim 2 wherein said linking apparatus is configured suchthat when said first operational member is at said first position andsaid second operational member is at said third position, the spacingbetween said first and second operational members is less than saidspacing when said first operational member is at said second positionand said second operational member is at said fourth position.
 7. An endeffector as claimed in claim 6 further comprising a fifth operationalmember, said fifth operational member not directly connected to saidactuation mechanism, said fifth operational member linked by saidlinking apparatus to said second operational member, wherein when saidactuation mechanism moves said first operational member from said firstposition to said second position, said second operational member ismoved by said linking apparatus from a third position to a fourthposition, and said fifth operational member is moved by said linkingapparatus from a ninth position to a tenth position, and when saidactuation mechanism moves said first operational member from said secondposition to said first position, said second operational member is movedfrom said fourth position to said third position, and said fifthoperational member is moved from said tenth position to said ninthposition.
 8. An end effector as claimed in claim 2 wherein said first,second, third, and fourth operational members are pick up membersadapted to pick up and release at least one item.
 9. An end effector asclaimed in claim 8 further comprising a vacuum source that isinterconnected to provide vacuum to said first, second third and fourthpick-up members, wherein said vacuum source creates a suction force at asuction location on each of said first, second, third and fourth pickupmembers, to lift and hold said at least one item.